Alkoxycarbonylphosphonic acid derivative brush control agents

ABSTRACT

Alkoxycarbonylphosphonic acids and alkylthiocarbonylphosphonic acids and esters and salts of these acids such as diammonium methoxycarbonylphosphonate are useful for regulation of the growth rate of plants.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of my copending applicationSer. No. 474,536, filed May 30, 1974, now U.S. Pat. No. 3,943,201, whichin turn is a continuation-in-part of my copending application Ser. No.397,723, filed Sept. 17, 1973, now abandoned, which in turn is acontinuation-in-part of my copending application Ser. No. 381,620, filedJuly 23, 1973, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to novel alkoxycarbonylphosphonic acids and(alkylthio)carbonylphosphonic acids and their use as plant growthregulants. The use of various carbamoylphosphonates for control of plantgrowth is known. For example, see U.S. Pat. No. 3,627,507 and GermanOffenlegungsschrift 2,040,367. However, neither of these referencessuggests the compounds of this invention. Further, some of the activecompounds within the scope of this invention are known. U.S. Pat. No.3,033,891 discloses esters and salts of (alkylthio)carbonylphosphonicacid, but the reference does not suggest the plant growth regulantactivity of these compounds.

SUMMARY OF THE INVENTION

Compounds of the formula ##STR1## wherein R is M; alkyl of 1 to 8 carbonatoms, optionally substituted with a chlorine, bromine, fluorine oriodine; alkenyl of 3 to 8 carbon atoms; or ##STR2## WHEREIN A ischlorine or methyl,

B is chlorine or methyl,

n is 0 or 1, and

m is 0 or 1;

R₅ is alkyl of 1 to 6 carbon atoms, alkenyl of 3 to 4 carbon atoms, orbenzvl;

X is oxygen or sulfur;

Y is oxygen or sulfur, provided that when Y is sulfur, X is sulfur; andwhen X is sulfur, R is not hydrogen;

M is hydrogen, sodium, lithium, potassium, calcium, magnesium, zinc,manganese, barium, or ##STR3## wherein R₁ is hydrogen, alkyl of 1 to 4carbon atoms, or hydroxyalkyl of 2 to 4 carbon atoms;

R₂ is hydrogen, alkyl of 1 to 4 carbon atoms, or hydroxyalkyl of 2 to 4carbon atoms;

R₃ is hydrogen, alkyl of 1 to 4 carbon atoms, or hydroxyalkyl of 2 to 4carbon atoms; and

R₄ is hydrogen or alkyl of 1 to 12 carbon atoms, provided that the totalnumber of carbon atoms in R₁, R₂, R₃, and R₄ is less than 16

Are useful as plant growth regulants. These compounds and salts areparticularly useful for retarding the growth of woody plants. Thecompounds and salts can be applied to plants by directly contacting theplants with the compounds or by applying the compounds or salts to thesoil in which the plants grow. Both of these modes of application areencompassed within the term "applying to plants" as used herein.

Preferred compounds of this invention include those compounds of FormulaI where

R is alkyl of 1 to 4 carbons, benzyl or M;

M is hydrogen, sodium, potassium or ammonium;

R₅ is alkyl of 1 to 3 carbons;

X is oxygen or sulfur, provided that when X is sulfur, R is nothydrogen; and

Y is oxygen.

The most preferred compounds of this invention aremethoxycarbonylphosphonic acid, diammonium methoxycarbonylphosphonate,ethyl sodium methoxycarbonylphosphonate, and methyl sodiummethoxycarbonylphosphonate.

The compounds of this invention having the formula ##STR4## where Z isoxygen or sulfur and R, M and R₅ are defined as above, provided thatwhen Z is sulfur, R is not hydrogen, are novel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The alkoxycarbonylphosphonic acids and (alkylthio)carbonylphosphonicacids of this invention are readily prepared by the interaction ofdialkyl alkoxycarbonylphosphonates or (alkylthio)carbonylphosphonateswith hydrogen iodide. Salts of these acids are prepared by reacting theacids with one or two equivalents of a base having the appropriatecation.

The dialkyl alkoxycarbonylphosphonates and(alkylthio)carbonylphosphonates which are precursors to the compounds ofthis invention can be prepared by a variety of methods available in theliterature, such as Nylen, Chem. Ber. 57, 1023 (1924), and Reetz et al.,JACS 77, 3813 (1955). The method comprises treating an appropriatetrialkyl phosphite with a chloroformate or thiolchloroformate.

The following Examples further illustrate the preparation of thecompounds of this invention.

EXAMPLE 1

Into a stirred solution comprised of 14.8 parts of dimethylmethoxycarbonylphosphonate and 100 parts of methylene chloride at(-)5° - (+)5° C. was added 30 parts of anhydrous hydrogen iodide. Thereaction was then allowed to warm to room temperature whereupon it wasstirred overnight. The bottom layer which formed was separated andevaporated under reduced pressure to afford 6.7 parts ofmethoxycarbonylphosphonic acid. The nmr spectrum (dmso-d₆) exhibitednone of the P-O-CH₃ doublet, but retained the COOCH₃ signal. The irshowed the ##STR5## at 1700 cm⁻ ¹ and the P--O at 1100 cm⁻ ¹.

By replacing the dimethyl methoxycarbonylphosphonate of Example 1 withthe appropriate dimethyl alkoxycarbonyl- or(alkylthio)carbonylphosphonate, the following compounds can be prepared.

    ______________________________________                                         ##STR6##                                                                     R.sub.5                                                                       ______________________________________                                        CH.sub.2CHCH.sub.2 CH.sub.2                                                   CH.sub.2CHCH.sub.2                                                            CH.sub.3 CH.sub.2                                                             (CH.sub.3).sub.2 CHCH.sub.2                                                   CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                         C.sub.6 H.sub.5 CH.sub.2                                                      CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                  ______________________________________                                    

example 2

to 50 parts of ammonium hydroxide containing a few pieces of ice wasadded with stirring 3 parts of methoxycarbonylphosphonic acid, theproduct of Example 1. The cooled solution was allowed to stir for 15minutes and was then evaporated under reduced pressure to afford thedesired diammonium methoxycarbonylphosphonate, m.p. 157° d.

By replacing the ammonium hydroxide of Example 2 with one or twoequivalents of the appropriate base or by routine cation exchangeprocedures, the following salts could similarly be prepared:

    ______________________________________                                         ##STR7##                                                                     R.sub.5        R             M                                                ______________________________________                                        CH.sub.3       Na            H                                                CH.sub.3       Na            Na                                               CH.sub.3       NH.sub.4      H                                                CH.sub.3 CH.sub.2                                                                            Ca            Ca                                               CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                        Li            Li                                               CH.sub.3       1/2 Mn        1/2 Mn                                           CH.sub.3 CH.sub.2 CH.sub.2                                                                   1/2 Zn        1/2 Zn                                           C.sub.6 H.sub.5 CH.sub.2                                                                     1/2 Ba        1/2 Ba                                           CH.sub.3       1/2 Mg        1/2 Mg                                           CH.sub.3       (CH.sub.2 CH.sub.2 OH).sub.3 NH                                                             H                                                CH.sub.3       (CH.sub.3).sub.2 NH.sub.2                                                                   (CH.sub.3).sub.2 NH.sub.2                        CH.sub.3       (C.sub.12 H.sub.25)NH.sub.3                                                                 H                                                CH.sub.3       (CH.sub.3).sub.3 N(C.sub.12 H.sub.25)                                                       H                                                CH.sub.2CHCH.sub.2                                                                           Na            Na                                               ______________________________________                                    

EXAMPLE 3

A mixture of 15.0 parts of sodium iodide and 8.4 parts of dimethylmethoxycarbonylphosphanate on 20 parts of 2-butanone was heated to 60°for 1 hour. The mixture was cooled and filtered to provide 8.0 parts ofthe desired methyl sodium methoxycarbonylphosphonate, mp 183° d.

EXAMPLE 4 Ethyl Sodium Methoxycarbonylphosphonate

A solution of 5.9 parts of diethyl methoxycarbonylphosphonate and 4.5parts of sodium iodide was stirred at room temperature in 50 parts oftetrahydrofuran for 60 hours. The resulting mixture was filtered to give3.5 parts of the desired ethyl sodium methoxycarbonylphosphonate, m.p.123° d.

In a similar manner, the following salts can be prepared from thedialkyl alkoxycarbonylphosphonates.

    ______________________________________                                         ##STR8##                                                                     R             R.sub.5         M     M.P., ° C.                         ______________________________________                                        C.sub.6 H.sub.5 CH.sub.2                                                                    CH.sub.3        Na    198-204                                   CH.sub.2CHCH.sub.2                                                                          CH.sub.3        Na    >300                                      CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                         CH.sub.3 CH.sub.2                                                                             Na    248 d                                     CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                         Na    Wax                                       CH.sub.3      CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                         Na    73-8                                      CH.sub.3      (CH.sub.3).sub.2 CHCH.sub.2                                                                   Na    154-6                                     CH.sub.3 CH.sub.2                                                                           C.sub.6 H.sub.5 CH.sub.2                                                                      Na    >300                                      ClCH.sub.2 CH.sub.2                                                                         CH.sub.3        Na    --                                         ##STR9##     CH.sub.3 CH.sub.2                                                                             Na    --                                         ##STR10##    CH.sub.3        Na    --                                        CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                       CH.sub.3 CH.sub.2                                                                             Na    --                                        FCH.sub.2 CH.sub.2                                                                          CH.sub.3        Na    --                                        ICH.sub.2 CH.sub.2                                                                          CH.sub.3        Na    --                                        BrCH.sub.2 CH.sub.2                                                                         CH.sub.3        Na    --                                        ______________________________________                                    

EXAMPLE 5

Passage of an aqueous solution of ethyl sodiummethoxycarbonylphosphonate through an appropriate acid ion exchangecolumn gives ethyl hydrogen methoxycarbonylphosphonate.

In a similar manner, the following hydrogen phosphonates can be preparedfrom the appropriate salts.

    ______________________________________                                         ##STR11##                                                                    R                R.sub.5                                                      ______________________________________                                        CH.sub.3         CH.sub.3                                                      ##STR12##       CH.sub.3 CH.sub.2                                            CH.sub.3         CH.sub.3 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                            CH.sub.3 CH.sub.2                                             ##STR13##       CH.sub.3                                                     CH.sub.3         C.sub.6 H.sub.5 CH.sub.2                                     CH.sub.2CHCH.sub.2                                                                             CH.sub.3 CH.sub.2                                            ClCH.sub.2 CH.sub.2                                                                            CH.sub.3 CH.sub.2                                            CH.sub.3 CH.sub.2                                                                              CH.sub.2CHCH.sub.2 CH.sub.2                                   ##STR14##       CH.sub.3                                                     CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                          CH.sub.3                                                     CH.sub.3 CH.sub.2                                                                              C.sub.6 H.sub.5 CH.sub.2                                     CH.sub.3         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2        CH.sub.3         CH.sub.2CHCH.sub.2                                           ______________________________________                                    

example 6

careful neutralization of an aqueous solution of methyl hydrogenmethoxycarbonylphosphonate with one equivalent of ammonium hydroxidegives the methyl ammonium methoxycarbonylphosphonate.

In a similar manner, the following phosphonate salts can be preparedfrom the appropriate hydrogen phosphonate and the appropriate base.

    ______________________________________                                         ##STR15##                                                                    R              R.sub.5      M                                                 ______________________________________                                        CH.sub.3 CH.sub.2                                                                            CH.sub.3     K                                                  ##STR16##     CH.sub.3     Na                                                (CH.sub.3).sub.2 CHCH.sub.2                                                                  CH.sub.3     Li                                                CH.sub.3       CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                        1/2 Ba                                            ClCH.sub.2 CH.sub.2                                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                                 NH.sub.4                                          CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                        CH.sub.2CHCH.sub.2                                                                         (HOCH.sub.2 CH.sub.2).sub.3 NH                    CH.sub.3       C.sub.6 H.sub.5 CH.sub.2                                                                   (C.sub.12 H.sub.25)NH.sub.3                       C.sub.6 H.sub.5 CH.sub.2                                                                     CH.sub.3     K                                                 CH.sub.2CHCH.sub.2                                                                           CH.sub.3     Na                                                ______________________________________                                    

Alternately, these salts can be prepared directly from the sodium saltsby conventional ion exchange methods.

EXAMPLE 7

Using the procedure described in U.S. Pat. No. 3,033,891, the followingsodium salts can be prepared.

    ______________________________________                                         ##STR17##                                                                                                        M.P.,                                     R             R.sub.5         M     ° C.                               ______________________________________                                        CH.sub.2CHCH.sub.2                                                                          CH.sub.3        Na    157° d                             CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                         CH.sub.3        Na    Wax                                       C.sub.6 H.sub.5 CH.sub.2                                                                    CH.sub.3 CH.sub.2                                                                             Na    --                                        CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                       CH.sub.3        Na    --                                        CH.sub.3      CH.sub.2 C.sub.6 H.sub.5                                                                      Na    --                                        CH.sub.3 CH.sub.2                                                                           CH.sub.2CHCH.sub.2                                                                            Na    --                                        (CH.sub.3).sub.2 CHCH.sub.2                                                                 CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                         Na    --                                        ______________________________________                                    

EXAMPLE 8 Ethyl Hydrogen (Methylthio)carbonylphosphonate

Passage of an aqueous solution of ethyl sodium(methylthio)carbonylphosphonate prepared as described in U.S. Pat. No.3,033,891 through an appropriate acid ion exchange resin gives ethylhydrogen (methylthio)carbonylphosphonate.

In a similar manner, the following hydrogen phosphonates can be preparedfrom the appropriate salts.

    ______________________________________                                         ##STR18##                                                                    R                R.sub.5                                                      ______________________________________                                        CH.sub.3         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                          CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                            CH.sub.3 CH.sub.2                                            CH.sub.2CHCH.sub.2                                                                             CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2        CH.sub.3 CHCHCH.sub. 2                                                                         CH.sub.3                                                     CH.sub.2CHCH.sub.2 CH.sub.2                                                                    CH.sub.3 CH.sub.2                                            CH.sub.3 CH.sub.2                                                                              CH.sub.2CHCH.sub.2                                           C.sub.6 H.sub.5 CH.sub.2                                                                       CH.sub.3                                                     ClCH.sub.2 CH.sub.2                                                                            CH.sub.3 CH.sub.2                                            ______________________________________                                    

example 9 methyl potassium (benzylthio)carbonylphosphonate

Careful neutralization of an aqueous solution of methyl hydrogen(benzylthio)carbonylphosphonate with one equivalent of potassiumhydroxide gives methyl potassium (benzylthio)carbonylphosphonate.

In a similar manner, the following salts can be prepared from theappropriate hydrogen phosphonate and the appropriate base.

    ______________________________________                                         ##STR19##                                                                    R              R.sub.5     M                                                  ______________________________________                                        CH.sub.3       CH.sub.3    K                                                  CH.sub.3 CH.sub.2                                                                            CH.sub.2CHCH.sub.2                                                                        NH.sub.4                                           (CH.sub.3).sub.2 CHCH.sub.2                                                                  CH.sub.3    (HOCH.sub.2 CH.sub.2).sub.3 NH                     C.sub.6 H.sub.5 CH.sub.2                                                                     CH.sub.3 CH.sub.2                                                                         1/2 Mn                                             ClCH.sub.2 CH.sub.2                                                                          CH.sub.3    Li                                                 CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                        CH.sub.3 CH.sub.2                                                                         1/2 Ba                                             CH.sub.2CHCH.sub.2                                                                           CH.sub.3    (CH.sub.3).sub.3 NH                                ______________________________________                                    

alternately, these compounds can be prepared by conventional ionexchange methods directly from the sodium salts.

EXAMPLE 10 Ethyl sodium (methylthio)thiocarbonylphosphonate

To a solution of 2.3 parts of diethyl(methylthio)thiocarbonylphosphonate in 50 parts of dry tetrahydrofuranwas added 1.5 parts of sodium iodide. The solution was stirred for 18hours at room temperature, then warmed on a steam bath for one-halfhour. The desired orange ethyl sodium(methylthio)thiocarbonylphosphonate was then filtered, m.p. 288° d.

EXAMPLE 11 Ethyl hydrogen (methylthio)thiocarbonylphosphonate

Passage of an aqueous solution of ethyl sodium(methylthio)thiocarbonylphosphonate through an appropriate acid ionexchange column gives ethyl hydrogen(methylthio)thiocarbonylphosphonate.

In a similar manner by use of the appropriate phosphonate salt, thefollowing compounds can be prepared.

    ______________________________________                                         ##STR20##                                                                    R                R.sub.5                                                      ______________________________________                                        CH.sub.3         CH.sub.3                                                     CH.sub.3         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                          CH.sub.3 CH.sub.2                                                                              CH.sub.2CHCH.sub.2                                           CH.sub.3 CH.sub.2                                                                              C.sub.6 H.sub.5 CH.sub.2                                     CH.sub.3                                                                                        ##STR21##                                                   CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                            CH.sub.3                                                     CH.sub.2CHCH.sub.2                                                                             CH.sub.3 CH.sub.2                                            C.sub.6 H.sub.5 CH.sub.2                                                                       CH.sub.3                                                     ClCH.sub.2 CH.sub.2                                                                            CH.sub.3 CH.sub.2 CH.sub.2                                    ##STR22##       CH.sub.3                                                     ______________________________________                                    

example 12 methyl barium (methylthio)thiocarbonylphosphonate

Careful neutralization of methyl hydrogen(methylthio)thiocarbonylphosphonate with one-half equivalent of bariumcarbonate gives methyl barium (methylthio)thiocarbonylphosphonate.

In a similar manner, the following phosphonate salts can be preparedfrom the appropriate hydrogen phosphonate and the appropriate base.

    ______________________________________                                         ##STR23##                                                                    R              R.sub.5      M                                                 ______________________________________                                        (CH.sub.3).sub.2 CHCH.sub.2                                                                  CH.sub.3     NH.sub.4                                          CH.sub.3       CH.sub.3 CH.sub.2                                                                          K                                                 CH.sub.2CHCH.sub.2                                                                           CH.sub.3     (C.sub.12 H.sub.25)NH.sub.3                       CH.sub.3       CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                        1/2 Zn                                            CH.sub.3       (CH.sub.3).sub.2 CHCH.sub.2                                                                (HOCH.sub.2 CH.sub.2).sub.3 NH                    CH.sub.3 CH.sub.2                                                                            C.sub.6 H.sub.5 CH.sub.2                                                                   1/2 Mg                                            C.sub.6 H.sub.5 CH.sub.2                                                                     CH.sub.3     Li                                                CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                        CH.sub.3 CH.sub.2                                                                          K                                                 ______________________________________                                    

alternately, these salts can be prepared directly from the sodium saltsby conventional ion exchange methods.

The compounds and salts of the invention are useful for modifying thegrowth of plants. The compounds and salts of this invention areparticularly useful for preventing bud break and retarding the growth ofwoody plants. Thus, the compounds and salts of this invention can beapplied in areas such as power line rights-of-way where low-growing andslow-growing vegetation is especially desirable.

In addition to their value as plant growth retardants, the compounds andsalts of this invention can also be used to control flowering, fruitset, and coloration on apples and other fruits. They are useful incontrolling the growth of viney plants such as morning glory and BlackValentine bean, and grasses such as crabgrass, barnyard grass, and corn.

The compounds and salts of this invention can also be used to prolongthe dormancy of perennial plants and thereby protect the unsprouted budsfrom frost damage. This can be especially important in the protection offlower buds, which in some years may sprout early and be killed by coldtemperatures. Application to plants in the stage where next year's budsare being initiated or are developing gives marked retardation of budbreak the following spring and greatly reduced growth.

To illustrate the growth retardant activity of the compounds and saltsof this case, the following data are presented.

In one test, the test compounds were applied in a solvent with a wettingagent and a humectant to cotton plants (five-leaf stage includingcotyledons), bush bean (second trifoliate leaf expanding), morning glory(four-leaf stage including cotyledons), cockebur (Xanthium sp.,four-leaf stage including cotyledons), Cassia tora (three leavesincluding cotyledons), nutsedge (Cyperus rotundus, three- to five-leafstage), crabgrass (Digitaria sp., two-leaf stage), barnyard grass(Echinochloa sp., two-leaf stage), wild oats (Avena fatua, one-leafstage), wheat (two-leaf stage), corn (three-leaf stage), soybean(two-cotyledons), rice (two-leaf stage), and sorghum (three-leaf stage).

Treated plants and controls were maintained in a greenhouse for sixteendays; then all species were compared with controls and visually ratedfor response to treatment.

    __________________________________________________________________________    POST EMERGENCE                                                                                         Bush     Morning                                                                            Cock-   Nut-                                                                              Crab-                      COMPOUND             Kg/Ha                                                                             Bean Cotton                                                                            Glory                                                                              lebur                                                                             Cassia                                                                            sedge                                                                             grass                      __________________________________________________________________________     ##STR24##           2   8G 2H 6F                                                                           8G  9C   7G 2C                                                                             6G  0   0                           ##STR25##            2  8G 1C 6Y                                                                           8G 2H                                                                             8G 2C                                                                              6G  6G 3C                                                                             0   3G                          ##STR26##            2  8G 5I 6Y                                                                           8G 2H                                                                             8G 2H                                                                              0   4G  0   0                           ##STR27##            2  9C 10D                                                                             7G 3C                                                                             8C   2G  3G  0   4G                          ##STR28##            2  9C 10D                                                                             5G  7G 2C                                                                              0   2G  0   2G                          ##STR29##            2  2C 5D                                                                              8G  10 C 2G  0   0   2G                          ##STR30##            2  3C   4G  6G 1C                                                                              0   0   0   3G                          ##STR31##           2   2C   4G  4G   3G  0   0   0                           ##STR32##            2  5G 1C                                                                               5G  3G   0   0   0   0                          ##STR33##           2   9D   5G 1C                                                                             5G   0   0   0   0                           ##STR34##            2  8G 4C 6Y                                                                            9G  6C   1H  2G  0   2G                        __________________________________________________________________________                             Barnyard                                                                           Wild         Soy-    Sor-                       COMPOUND             Kg/Ha                                                                             Grass                                                                              Oats                                                                              Wheat                                                                              Corn                                                                              bean                                                                              Rice                                                                              ghum                       __________________________________________________________________________     ##STR35##           2   7G 2C                                                                              0   0    7G 2U                                                                             6G  0   6G 1C                       ##STR36##            2  7G 2C                                                                              0   2G   7G 2U                                                                             5G 1C                                                                             0   7G 2U                       ##STR37##            2  4G   0   0    7G 2U                                                                             6G  0   1C                          ##STR38##            2  7G 2C                                                                              4G 2C                                                                             4G   7G 1C                                                                             3G  0    6G 1C                      ##STR39##            2  8G   3G  3G   5G 1C                                                                             5G  0   5G 1C                       ##STR40##            2  0    0   0    6G 2C                                                                             0   0   0                           ##STR41##            2  0    0   0    6G 1C                                                                             0   0   0                           ##STR42##           2   0    0   0    2G  0   0   0                           ##STR43##            2   0    0   0   5G 1C                                                                              0   0   0                          ##STR44##           2   2C   0   0    5G 1C                                                                             0   0   0                           ##STR45##           2   8C   1H  2G   8G 1C                                                                             9P  2G  7G 2C                      __________________________________________________________________________

in another test, the test compounds were applied in a similar solvent topots of bean (Phaseolus vulgaris cv. Black Valentine), apple (Malussp.), and willow (Salix sp.). The plants were maintained in agreenhouse, and plant response ratings were taken after application asindicated.

    __________________________________________________________________________                   Black                                                                         Valentine                                                                     Bean     Apple    Willow                                                  Rate,                                                                             One  Four                                                                              One Four One Four                                                kg/ha                                                                             Week Weeks                                                                             Week                                                                              Weeks                                                                              Week                                                                              Weeks                                    __________________________________________________________________________     ##STR46## 1 4 9G2H 10G                                                                           8G 8G                                                                             0 0 0 0  3G 9G5X                                                                           -- 5G3X                                   ##STR47## 1 4 8G 10G10P 2C                                                                       7G 8G                                                                             6G 0                                                                              2G 0 2G 8G5X                                                                           0 2G2X                                    ##STR48## 1 4 5G10P 9G10P                                                                        7G 9G5C                                                                           0 0 9G1C 10G                                                                           6G 10G                                                                            3G5X 9G5X                                 ##STR49##  1 4                                                                              2G 8G10P                                                                           4G 9G                                                                             0 0 4G 6G                                                                              0 9G                                                                              0 9G3X                                    ##STR50## 1 4 9G10P 8G10P                                                                        10D 10G                                                                           0 0 6G 10G2C                                                                           6G 10G                                                                            8G5X 9G                                   ##STR51## 1 4 6G 8G10P                                                                           8G3X 10D                                                                          0 1H                                                                              0 10G2H                                                                            5G 9G                                                                             6G5X 9G3X                                __________________________________________________________________________

the plant response ratings above are composed of a number and a letter.The number describes the extent of the response and ranges from zero toten, with zero representing no response and ten representing 100%response. As for the letters, "G" represents growth retardation, "P"represents terminal bud kill, "H" represents hormonal effects, "C"represents chlorosis, "U" represents unusual pigmentation, "I"represents increased chlorophyll, "D" represents defoliation, "X"represents axillary stimulation, "6Y"* represents abscised buds orflowers, "7Y"* represents a decreased number of buds or flowers, and"6F"* represents delayed flowering.

The term "plant growth retardant" as used in this disclosure is to beunderstood to mean an agent which, when applied to a plant or itsenvirons, will slow the growth of the plant. This also includes adelaying response on bud sprouting or prolonging of the dormancy period.

The compounds and salts of this invention can be applied as foliarsprays or as soil applications to retard the growth rate of such plantsor to affect flowering and fruit set.

Preferably, the compounds and salts of this invention are applied asfoliar or dormant wood sprays to the point of runoff, althoughlower-volume application can also be effective.

The compounds and salts of the invention are very versatile and may beapplied at one of many different time periods to suit the convenience ofthe applicator. For example, they may be applied in spring a short timeprior to the period when maximum plant growth is anticipated, to effectgrowth retardation; they may be applied later in the growing season,just after trimming, to effect growth retardation; or they may beapplied when the year's growth has ceased (later summer, fall, orwinter) with the result that treated plants will remain dormant thefollowing spring; whereas untreated plants will sprout and grow. Ifflowering and fruit set are to be modified, the treatment is appliedbefore, during, or shortly after flowering.

It will be recognized that the application rate is dependent upon thespecies to be treated and the results desired. In general, rates of from0.25 to 20 kilograms per hectare are used, although higher or lowerrates can achieve the desired effect in some instances.

Useful formulations of the compounds and salts of this invention can beprepared in conventional ways. They include dusts, granules, pellets,solutions, suspensions, emulsions, wetting powders, emulsifiableconcentrates, and the like. Many of these may be applied directly.Sprayable formulations can be extended in suitable media and used atspray volumes of from a few pints to several hundred gallons per acre.High-strength compositions are primarily used as intermediates forfurther formulation. The formulations, broadly, contain about 1% to 99%by weight of active ingredient(s) and at least one of (a) about 0.1% to20% surfactant(s) and (b) about 5% to 99% solid or liquid diluent(s).More specifically, they will contain these ingredients in the followingapproximate proportions:

    ______________________________________                                                     Percent by weight                                                             Active                                                                        Ingre-  Dilu-     Surfac-                                                     dient   ent(s)    tant(s)                                        ______________________________________                                        Wettable Powders                                                                             20-90      0-74     1-10                                       Oil Suspensions                                                                and Emulsions  5-50     40-95     0-15                                       Aqueous Solutions                                                                            10-50     50-90     0-20                                       Dusts           1-25     70-99     0-5                                        Granules and Pellets                                                                          1-95      5-99     0-15                                       High-strength                                                                  Compositions  90-99      0-10     0-2                                        ______________________________________                                    

Lower or higher levels of active ingredient can, of course, be present,depending on the intended use and the physical properties of thecompound. Higher ratios of surfactant to active ingredient are sometimesdesirable and are achieved by incorporation into the formulation or bytank-mixing. Likewise, high levels of oils or humectants can beincorporated, either in the formulation or by tank-mixing.

Typical solid diluents are described in Watkins et al., "Handbook ofInsecticide Dust Diluents and Carriers", 2nd Ed., Dorland Books,Caldwell, N.J. The more absorptive diluents are preferred for wettablepowders and the denser ones for dusts. Typical liquid diluents andsolvents are described in Marsden, "Solvents Guide", 2nd Ed.,Interscience, N.Y., 1950. Solubility under 0.1% is preferred forsuspension concentrates; solution concentrates are preferably stableagainst phase separation at 0° C. "McCutcheon's Detergents andEmulsifiers Annual", Allured Publ. Corp., Ridgewood, N.J., as well asSisely and Wood, "Encyclopedia of Surface Active Agents", Chemical Publ.Co., Inc., N.Y., 1964, list surfactants and recommended uses. Allformulations can contain minor amounts of additives to reduce foam,caking, corrosion, microbiological growth, etc. Preferably, ingredientsshould be approved by the U.S. Environmental Protection Agency for theuse intended.

The methods of making such compositions are well known. Solutions areprepared by simply mixing the ingredients. Fine, solid compositions aremade by blending and, usually, grinding, as in a hammer or fluid energymill. Suspensions are prepared by wet-milling (see, for example,Littler, U.S. Pat. No. 3,060,084). Granules and pellets may be made byspraying the active material upon preformed granular carriers or byagglomeration techniques. See J. E. Browning, "Agglomeration", ChemicalEngineering, Dec. 4, 1967, pp. 147 ff. and "Perry's Chemical Engineer'sHandbook", 4th Ed., McGraw-Hill, N.Y., 1963, pp. 8-59 ff.

For further information regarding the art of formulation, see, forexample:

H. m. loux, U.S. Pat. No. 3,235,361, Feb. 15, 1966, Col. 6, line 16through Col. 7, line 19, and Examples 10 through 41

W. p. langsdorf, U.S. Pat. No. 3,627,507, Dec. 14, 1971, Col. 8, line 1,through Col. 11, line 12, and Examples 60-65

G. c. klingman, "Weed Control as a Science", John Wiley & Sons, Inc.,N.Y., 1961, pp. 81-96

J. d. fryer and S. A. Evans, "Weed Control Handbook", 5th Ed., BlackwellScientific Publications, Oxford, 1968, pp. 101-103

The following Examples further illustrate the formulation andapplication of the compounds of this invention.

EXAMPLE 13

    ______________________________________                                        Water-soluble Powder                                                          ______________________________________                                        diammonium methoxycarbonylphosphonate                                                                    95.0%                                              dioctyl sodium sulfosuccinate                                                                            0.5%                                               sodium ligninsulfonate     1.0%                                               synthetic fine silica      3.5%                                               ______________________________________                                    

The ingredients are blended and coarsely ground in a hammer mill so thatonly a small percent of the active exceeds 250 microns (U.S.S. #60sieve) in size. When added to water with stirring, the coarse powderinitially disperses and then the active ingredient dissolves so that nofurther stirring is needed during application.

Ten kilograms of this formulation are dissolved in 800 liters of watercontaining 0.5% of a nonphytotoxic wetting agent. This formulation issprayed from a helicopter to a one-hectare area under an electric powerline in which the brush and trees have been freshly trimmed. Thistreatment retards the growth of black willow (Salix nigra), black cherry(Prunus serotina), and many other woody species.

The following can be formulated and applied in a similar manner withsimilar results.

ethyl sodium methoxycarbonylphosphonate

methyl sodium methoxycarbonylphosphonate

methyl sodium ethoxycarbonylphosphonate

ethyl sodium ethoxycarbonylphosphonate

ethyl sodium (methylthio)carbonylphosphonate

methyl sodium (ethylthio)carbonylphosphonate

EXAMPLE 14

    ______________________________________                                        Wettable Powder                                                               ______________________________________                                        diammonium methoxycarbonylphosphonate                                                                     40%                                               dioctyl sodium sulfosuccinate                                                                             1.5%                                              sodium ligninsulfonate      3%                                                low viscosity methyl cellulose                                                                            1.5%                                              attapulgite                 54%                                               ______________________________________                                    

The ingredients are thoroughly blended, passed through an air mill, toproduce an average particle size under 15 microns, reblended, and siftedthrough a U.S.S. No. 50 sieve (0.3 mm opening) before packaging.

All solid compounds of the invention may be formulated in the samemanner.

Fifteen kilograms of this formulation are mixed with 600 liters of waterin a sprayer fitted with an agitator. The mixture is sprayed on a onehectare area of newly trimmed hedgerow in the spring after the leaveshave expanded. (The spray may be either directly on the plants or to thelocus of the plants.) This treatment greatly reduces the growth ofplants growing in the hedgerow but does not seriously injure them. Thus,the hedgerow is kept neat with a minimum of labor expended for trimmingit.

EXAMPLE 15

    ______________________________________                                        Solution                                                                      ______________________________________                                        methoxycarbonylphosphonic acid                                                                           20.0%                                              octylphenoxypolyethoxyethanol                                                                             0.5%                                              water                      79.5%                                              ______________________________________                                    

The ingredients are combined and stirred to produce a solution which canbe applied directly or after dilution with additional water. Allsufficiently soluble compounds of the invention may be formulated insimilar fashion.

Fifteen liters of this solution are mixed with 200 liters of water andsprayed in late Summer on a one hectare area of woody plants growing ona power line right-of-way. The treated plants continue to appear likeuntreated plants. However, the following year the treated plants remaindormant for an extremely long period of time, whereas untreated onessprout and grow normally. Thus the treatment greatly reduces the amountof labor required to maintain the plants at a desirable height.

I claim:
 1. A method of retarding plant growth consisting essentially ofapplying to the plant an effective amount of ##STR52## wherein R is M;alkyl of 1 to 8 carbon atoms, optionally substituted with a chlorine,bromine, fluorine, or iodine; alkenyl of 3 to 8 carbon atoms; or##STR53## wherein A is chlorine or methyl, B is chlorine or methyl, n is0 or 1, and m is 0 or 1; R₅ is alkyl of 1 to 6 carbon atoms, alkenyl of3 to 4 carbon atoms, or benzyl; M is hydrogen, sodium, lithium,potassium, calcium, magnesium, zinc, manganese, barium, or ##STR54##wherein R₁ is hydrogen, alkyl of 1 to 4 carbon atoms, or hydroxyalkyl of2 to 4 carbon atoms;R₂ is hydrogen, alkyl of 1 to 4 carbon atoms, orhydroxyalkyl of 2 to 4 carbon atoms; R₃ is hydrogen, alkyl of 1 to 4carbon atoms, or hydroxyalkyl of 2 to 4 carbon atoms; and R₄ is hydrogenor alkyl of 1 to 12 carbon atoms, provided that the total number ofcarbon atoms in R₁, R₂, R₃, and R₄ is less than
 16. 2. The method ofclaim 1 whereinR is hydrogen, alkyl of 1 to 4 carbon atoms, or benzyl;R₅ is alkyl of 1 to 4 carbon atoms; and M is hydrogen, sodium,potassium, or ammonium.
 3. The method of claim 2 wherein the compound isethyl sodium methoxycarbonylphosphonate.
 4. The method of claim 2wherein the compound is methyl sodium methoxycarbonylphosphonate.
 5. Themethod of claim 1 wherein the compound is diammoniummethoxycarbonylphosphonate.
 6. The method of claim 2 wherein thecompound is methoxycarbonylphosphonic acid.
 7. The method of claim 2wherein the plant is a woody plant.
 8. The method of claim 2 wherein theplant is a viney plant.
 9. The method of claim 2 wherein the plant is agrass.